Mortimer "Mort" Daniels is Mickey Daniels' baby brother in two appearances. In Circus Fever, Mickey has to give Mortimer a bath. Jackie Condon is also their brother in that short. In Dog Days, Mickey and Mortimer's mother tells Mickey he must watch the baby. Encouraged by the Gang, Mickey attempts to get his dog to watch Mortimer and notify Mickey if Mort wakes up. The dog fails, but redeems himself by rescuing Mary on a runaway pony-drawn carriage.
The baby who played Mortimer is unknown.